Melting/Forming Platic Fuel Tank?

[CJM]

Im needing to melt/form a very small area on a plastic fuel tank so it can clear a different carb than stock.

Never did this before, have welded metal tanks but we usually fill them with water. Im not sure if I were to fill a tank with water would I be able to take a torch to heat up the plastic enough to make it malleable and form it a bit?

Anyone done this before?

[finsteratv]

check the hybrid section..maybe heat gun?

[jesshamner]

Witech has done it before on a Cannondale tank. I think he used a heat gun and a giant spoon to shape it.

I would think that you would need to take your time and work it slowly so not to stretch the plastic too thin.

[CJM]

I didnt think a heatgun would get hot enough, was thinking a torch held a bit away from the tank. Mostly worried the fumes will combust.

[tayyo789]

I reformed the whole bottom of mine on my hybrid. I drained the tank, and flushed it a few times, and put probably about a half gallon of water in it. I used a heat gun, and it worked fine. Just a little slower. To form it once it was soft, I used a spoon, a steel pipe, basically anything hard and round, and worked very slowly. Every time I felt it was getting too hot and soft, I would flip the tank right side up, which would let the water come down and cool the plastic. It was actually a lot easier than I expected it to be.

[CJM]

Thanks tayyo, think that will work just fine.

[tayyo789]

Just remember to go slow, heat a larger area then you need, and only use as much heat as needed. It would really suck to blow a hole through a perfectly good tank when they're so expensive to replace.

[crownandmonster]

I'm an electrician by trade and we use heat guns all the time to bend/form PVC conduit. Most heat guns will reach 1000 degrees when on high. Don't hold the gun in one spot to long keep it moving slowly back and forth. Make sure to heat up an area at least twice as big as you need to form, it helps to prevent stretching the plastic to thin in the spot you are working on. A dish cloth or similar soaked in cold water will help cool it down fast enough to keep its shape.